Cook onion in butter till transparent, in a large 3-quart saucepan.
In the same pan, blend in the flour and salt.
Add the sour cream gradually; keeping texture smooth.
Bring mixture to a boil, then add the frozen corn and parsley.
Reduce the heat, and cook till corn is heated through, then fold in half of the bacon.
Pour bacon/corn mixture into a greased 1 quart baking dish.
Garnish casserole with the remaining bacon.
Bake in oven (uncovered) for 30 minutes, then serve immediately.
*Note: For this recipe, I used thick-sliced bacon, and the brand of frozen corn I used, was Birds Eye Freshlike Cut Golden Corn, as it's a sweet tasting corn. (And yes, I used exactly 18 ounces of the frozen corn in this recipe!)